


Through A Glass Darkly

by TAFKAB



Category: Star Trek: The Original Series
Genre: Anal Sex, Coerced Consent, Credit to writer Jerome Bixby, Dubious Consent, Emotional Manipulation, Loss of Innocence, Loss of Virginity, M/M, Mindfuck, Mirror Universe, Oral Sex, Psychological Torture, Rape/Non-con Elements, Rimming, Some dialog borrowed from the original episode Mirror Mirror, Telepathy, Twisted, Virgin Spock
Language: English
Status: Completed
Published: 2016-09-20
Updated: 2016-09-20
Packaged: 2018-08-16 08:08:56
Rating: Explicit
Warnings: Rape/Non-Con
Chapters: 1
Words: 8,142
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/8094559
Author URL: https://archiveofourown.org/users/TAFKAB/pseuds/TAFKAB
Summary: When a crewman is severely injured during the crew transfer incident from Mirror, Mirror, Spock must strike a distasteful bargain with the ISS version of McCoy in order to obtain treatment for her.  The similarities between the two McCoys are as compelling and seductive as their differences are loathsome, as Spock learns when Mirror McCoy uncovers secrets about all four of them.  What he learns threatens to bring Spock both literally and figuratively to his knees.





	

**Author's Note:**

> _”Jim, if we're here, what do you suppose our counterparts are doing back in our universe?”_ \-- Lt. Commander and CMO Leonard McCoy, temporarily stranded aboard the ISS Enterprise, asking all the right questions

It was pure misfortune that Crewman Harris managed to deglove her hands working in the Jeffries tube while the Enterprise was experiencing an interdimensional personnel exchange incident. Even worse for her, one of the affected personnel was the ship’s surgeon, and the nerve damage was so extensive Chapel couldn’t handle it on her own. 

Spock listened to Chapel’s report calmly and nodded, steepling his fingers. “I will consult with the alternative Dr. McCoy. It is likely he possesses the skills necessary, if he can be persuaded to use them.”

Chapel bit her lip and acquiesced with reluctance; she’d been among the first to report an anomaly in the returned crew. She’d come to Spock for help when the alternative McCoy started working on people without bothering to use anesthesia. Spock was forming his own dubious opinions of the captain’s doppelganger by that time; between the two sets of suspicions, a conclusion was formed and the personnel swiftly isolated before further harm could be accomplished.

He gave Sulu the conn and apprised Mr. Scott of his whereabouts, then went down to the brig, riding quietly in the turbolift as he considered possibilities. He sensed the request would pose considerable difficulty, but no alternative presented itself. 

It took four security guards to, as Doctor McCoy might have put it, ‘cut the alternative doctor out of the herd,’ for the group resisted separation. The doppelganger of Kirk in particular was reluctant to let McCoy depart with Spock. Two of the security team sported bruises and cuts afterward, but Chapel could attend those quite competently. The security team escorted Spock and the alternate doctor down to sickbay, where Spock sequestered them in McCoy’s office and dismissed the guards to have their injuries mended.

“We have an emergency medical situation,” Spock informed him, terse. “None but your counterpart, and presumably yourself, are qualified to handle it.”

The man raised a mocking brow, sensing power, and went to sit in McCoy’s chair, putting his feet up on McCoy’s desk. “Saurian brandy?” He looked in the desk drawer and a smirk creased his face. “The good stuff.” He poured himself a stiff belt, moving slowly, doubtless intending to annoy Spock with the delay.

“Are you willing to treat Crewman Harris?”

“Well, that depends.” The drawl was pure McCoy, lazy and insolent-- but also sharp. It was something about the eyes, which fixed on Spock with a glitter. “What’s in it for me?”

Spock considered potential bartering materials. Freedom was out of the question. He did not think this man could be bought with food or drink. Perhaps he would accept money or valuables in sufficient quantity, if enough could be assembled.

“What do you desire?”

McCoy bit back some of the dark liquor and savored it on his palate before swallowing. “Interesting you should choose to put it that way.”

Spock raised a brow at him.

“I’ll patch up your crewman, good as new. Hell, I’ll even dope her up so she doesn’t scream while I’m doing it.” He smiled, falsely disarming, but those predatory eyes never left Spock’s. “In exchange for an evening with you.”

Both Spock’s brows went up, and he sat very still. There was no possibility that this version of the doctor intended for the two of them to spend that evening drinking brandy or even playing chess.

“An evening in which you agree to serve me sexually, yes. You’ll do whatever I want.” 

Spock knew without question he would pay that price to ensure Crewman Harris’s ability to use her hands once more; his modesty was a small cost in exchange for her happiness and livelihood. Still, he tilted his head. “Your request is not logical.”

“I’m an illogical man, Mr. Spock.” The alternative grinned at him, so like his own McCoy in a mischievous mood that Spock could almost have fooled himself into believing it was the same person. 

It was not.

“You haven’t ever had him, I take it. This universe is full of fools.” McCoy considered the amber fluid remaining in the tumbler. “My own Spock, now… he doesn’t waste time on pussy-footing around.” He tipped his head back, staring at the stuffed lizard on the opposite wall. “We have a long-term understanding. Whenever he needs release, I service him, and his patronage provides considerable protection for me. So tell me. How much do you want your crewman to regain the use of her hands?”

“I fail to see why I would be an acceptable substitute for an established--”

McCoy huffed amiably. “My Spock… he’s dark chocolate. 90% cacao with plenty of cayenne mixed in. You… it looks to me like you’re vanilla and whipped cream... with a cherry on top.” The eyes sharpened suddenly, predatory, and his grin was full of teeth. “I think maybe you’d taste a little better if I took that cherry and replaced it with some chocolate sprinkles.”

Spock did not deign to dignify that with a response; there was little time to waste. “Assist Crewman Harris competently, and I will make myself available to you as requested.” He spoke stiffly, stony. “I expect you to restore both full function and acceptable appearance.”

“I aim to please.” The alternative McCoy set aside the remains of his drink. “Lead me to her.”

*****

Spock supervised the procedure personally. This man might not have the more personable qualities of his own McCoy (the original McCoy, he amended hastily), but he had the same sure hands and dazzling skill. He worked efficiently, barking unfriendly orders to Chapel, who obeyed him with competent haste. Spock watched with fascination as McCoy put the tattered skin back on and knit it together, regenerating severed nerves and tendons capably, one by one.

It was only about 1500 hours when the surgery ended.

“What do you think, Chris?” McCoy drawled the question, insolent, a little too self-satisfied.

Chapel flashed Spock a nervous look. “Prognosis is good, doctor. She should be back to normal within the week.”

“Your part of our bargain starts now, Commander.” The alternative McCoy rocked on his toes, the familiarity of the gesture giving Spock a pang of nostalgia for the McCoy native to this universe, who would never have struck such an odious deal. The Leonard McCoy he knew would surely never desire sex with Spock, and if he did, he would not barter for it. The very notion would be repugnant to him. 

“Nervous?” The false McCoy raised a brow.

Intensely. “I am not,” he lied, feigning serenity. When cleanup was finished, he secured the doppelganger to his wrist with a set of metal binders and led him into the corridor, ignoring curious stares from various crewmen in the halls. 

He did not make haste, unsure at first of their destination. He did not wish for this to take place in his own quarters; nor did he feel it appropriate to conduct the liaison in the original Doctor McCoy’s rooms. He, at least, was innocent in this. Let him remain so.

After a moment’s deliberation he selected an unoccupied space reserved for visiting dignitaries, one supplied with a larger-than-usual bed (for married couples) and a replicator. The furnishings were bland, utilitarian and inoffensive. 

McCoy wrinkled his nose at the place, but went in, looking around with curiosity as Spock released the cuff that bound them together. “Nice big bed. It’ll do.” He sat down on it and yanked off his boots, letting them drop. He glanced sidelong at Spock, who stood next to the door, wrists clasped behind his back. “Rustle up some massage oil and rub my feet.”

Spock went to the replicator, moving without haste. It was a menial task, but preferable to filling the time with more explicitly sexual contact. 

“I’ve wanted you on your knees in front of me for a long time,” McCoy sighed, extending his bony feet. They were well-maintained, callus-free, the nails neatly groomed, with high arches and neat, symmetrical pink toes. Spock carefully lowered himself to his knees before them. The carpeting was thick enough to keep him from experiencing serious patellar discomfort. 

“Look at you… all you need is the beard.” McCoy sighed as Spock poured oil into his palm and spread it over the instep of one foot. “And enough sense to nerve pinch any man who coerces you into a bargain instead of keeping your word to him. But I’ll just be grateful you’re like you are, for the moment.”

McCoy watched as Spock spread the oil and began to massage. It was not an area in which Spock had cultivated knowledge or expertise, but as he had neglected to bring gloves, he was subject to the emanations from the alternate McCoy’s mind, and could judge his success or failure according to the man’s sensory responses.

McCoy was pleased for now; Spock could sense how much he liked looking down and seeing Spock’s glossy black head bent over him, Spock’s long fingers kneading his feet. He experienced pleasure in the massage, as well-- and Spock was startled to realize McCoy was aware of the mental touch. He had enough familiarity with telepathic contact that he could make himself privy to Spock’s unguarded external thoughts. 

“Oh yes. No secrets from me,” he laughed softly. “I can read you like a book.” 

Spock hastily erected his mental shields, but it was too late to retrieve anything that had already slipped. 

“You’re worried for him.” McCoy leaned back against the partition, gazing down with lips parted. “You should be, you know.”

Spock looked up, at first to deny the charge, then with growing alarm. 

“My Spock won’t leave him alone. Not if he’s as sweet and innocent as you are-- he’ll think that’s _fascinating_. He’ll snap him up like _that_.” He clicked his fingers crisply to illustrate. “He takes what he wants when he wants it. He’ll take him right away.” He surveyed Spock, who knelt motionless, forgetting to move his fingers. “And him, well.” His eyes gleamed with a delight that was almost malevolent. “It’ll be rough and it’ll be hot and he’ll like it. He’ll _love_ it. I can vouch for that. He’s dreamed about you for a long time, Spock. I’m sure of it.”

Spock felt wrath burn and seethe in him like the twisting of a red-hot knife. The man could wield his tongue like a laser scalpel, targeting and flaying open the most vulnerable feelings. He had an instinctive talent for locating weak spots-- even his own McCoy had that ability. 

“I’m bored with this.” McCoy lay back, stretching his arms luxuriantly over his head. “I want your mouth.”

Spock contemplated the request, considering and rejecting a number of deliberately obtuse misinterpretations of its obvious intent. He decided not to indulge the man’s cruelty with a show of reluctance, instead reaching to remove McCoy’s trousers. He saw no reason to romanticize the event, moving with simple efficiency. Belt. Button and zip. Fingers under the waistband, hooking in the elastic of underpants. A tug-- clumsy; he did not know the doctor was fully aroused, did not anticipate that his erection might snag in the fabric.

McCoy hissed, reaching to take over, catching his wrist. He held it tight as he dragged the cloth down in his other hand, hitching his hips aloft to help it on its way. 

“This isn’t how you’d have wanted things to go with him, is it?” He speculated, his lips turning up on one side-- again, the very image of Spock’s McCoy. The original McCoy! Spock chided himself with sudden sharpness. “You’d have wanted him to court you slow and easy: wined, dined, and sixty-nined. Or you’d have wanted to overwhelm him with your attention, unexpected.” He considered. “So you could win. Either way, you’d be in charge in the end. Right, Spock?”

Spock refused to rise to the bait-- or perhaps he did exactly what McCoy wanted; his passivity allowed the man to clasp his head and direct him downward. 

The doppelganger smelled of musk and sharp, cut grass; he was hard, the tip of his cock gleaming. Unlike Spock, he was circumcised, and the glans looked oddly bare without its protective sheath. Barbaric, to perform unnecessary surgery on an infant. He felt distinctly uncomfortable knowing such an intimate detail about McCoy and his parents’ choices.

His thoughts were a poor refuge; they did not forestall the alternate McCoy’s desires. He steadied his cock, and though Spock initially resisted the pressure from the hand at the back of his neck, McCoy painted Spock’s lips leisurely with the wetness from the tip. 

“And you promised so nicely,” he chided. 

Spock closed his eyes and opened his mouth. The human tasted of salt.

“No biting.” The hand curved around his jaw, thumb sweeping over the lobe of his ear, and returned to his neck. “Done this before? No? I thought not.” The doctor’s hand was at odds with the sharpness of his voice; it moved tenderly on him, and made him think of his own-- of the other-- of the original McCoy. He breathed through his nostrils, remaining still. _Surgeon’s hands._

“Suck,” the doctor urged, hand urging him gently forward, expecting him to take more.

Spock refused to look up, but he obeyed, hollowing his cheeks and beginning to move, tentative. He could have incapacitated McCoy, it was true, but he was a man who kept his word. That was the only reason he complied. 

“So Vulcans here can lie too,” McCoy murmured. “Even to themselves, it seems. You can’t hide from me, Spock. You want this.”

Spock’s eyes flew open; with chagrin, he realized his shields had slipped. Blue eyes, impossibly blue, looked back. It was too easy for their minds to touch; there was an affinity here that spoke of something more than strangers. It was as if there were already a link between them, or as if there once had been one, paving the way for McCoy to slip through his defenses. Impossible. 

“Oh, you do look good like this,” the familiar voice descended into a lazy drawl. “I have a link with my own Spock, you know.” His fingers ruffled Spock’s hair, a pleasant caress of fingertips against his scalp. “It seems you two are similar enough there’s a resonance.”

Spock shivered despite himself, struggling suddenly with the cock in his mouth as McCoy lifted his hips and it nudged against the back of his throat. 

“Tilt your head,” McCoy murmured, strangely tender. “Like that.”

It was easier than Spock had anticipated to take more-- and more, until his nose pressed against McCoy’s belly, the wiry hair there tickling him, smelling of musk and salt and clean soap. 

“I suppose I could learn to enjoy vanilla,” McCoy stroked his hair. “Whenever you’re ready.” Again he made it a request, not a demand.

Spock bobbed his head, a simple motion complicated only a little by his gag reflex. He chafed against his own obedience but felt strangely powerless to change it. He kept the motions stiff and mechanical, trying to remain emotionless. Yet he could not tear his eyes from McCoy’s face; the doctor’s lashes sank as his expression softened with pleasure, half-lidding those bright blue eyes. His lips curved, so like the original it made Spock’s heart ache-- and he realized he was moving faster, as if some part of him were eager.

As if it were--

Spock forced his eyes to close, locking himself inside the darkness within his head. 

“You don’t want me to be him.” McCoy’s voice resonated through him, low and husky. “This is too like him for you, isn’t it? You want me to be rough and savage with you, so you can hate me for this.” His hands were gentle, though that exultant note lingered in his voice, that faint trace of glee. “Sorry. Not gonna happen.”

Spock pulled off, turning his face aside, but found himself unable to choose words to speak. 

“Your doctor may not have the good sense to go for it, but I’m not wasting my shot at you.” Those hands came back, and this time they reached for his shirts, pulling the dark undershirt out of his trousers, working both garments over his head. “You even have the same scars,” he murmured with sudden wonder in his tone, and his fingertips traced the pale line that had been a long, terrible gash down Spock's chest, healed efficiently by the original McCoy no more than six months ago. “How the hell that’s possible I don’t even know.”

“It was a sword on Deneb VI.”

“The magistrate tried to defend the king’s daughter when Kirk wanted her as part of the tribute.”

“The magistrate attacked Kirk for using an incorrect honorific to the crown princess.”

They looked at one another for a long moment. McCoy’s fingertips moved up and down tenderly along the scar. 

“The odds against such divergent, yet parallel, events are astronomical. They indicate the interference of an outside agency, not random quantum proba--”

“Spock.” McCoy reached to touch his face, and Spock felt his amusement, aggravation, fondness. 

Fondness. He had not thought to experience such a thing tonight.

“Let go and enjoy it. Who’s gonna know?” The voice was soft, a little raspy, seductive. The voice of his dreams.

To silence him, Spock returned to his task, moving with more purpose now, hoping to give the false doctor his climax so that he could leave before the man forced Spock to face any other unpleasant truths about himself, about the McCoy who was gone now, in the hands of… he had no idea what sort of version of himself. He had too good an idea.

McCoy was rapidly succumbing to pleasure, too involved now to speak or taunt him, his breath coming hoarsely in his chest. Spock anticipated that he would wish to experience orgasm without withdrawal, and did not try to pull away as the human’s breathing grew more rapid and shallow, his hands quivering on Spock as he fought to delay his inevitable climax. 

Spock continued, patient; the effort did not require all his focus. It troubled him that he knew how McCoy sounded now when he was aroused. What he looked like, how he felt. Soon he would know--

The taste flooded over Spock’s tongue as McCoy’s low cry rang in his ears. Human, metallic, not wholly pleasant… a viscous texture. Too salty, too sharp. 

Now he knew.

Spock swallowed by instinct and remained where he was, his head bent, as McCoy slid out of his mouth. The other Spock must not allow such things; McCoy looked blissful, abandoned, triumphant. He milked a last few drops from himself, then lifted Spock’s chin, and Spock reluctantly accepted them, licking him clean.

“You’d better be glad you didn’t wind up over there with my Spock still in residence,” McCoy murmured at last. “I think he’d enjoy taking _you_ for a pet. He’s perverse enough.”

“I would not let him.” Spock’s spine stiffened with outrage at the very idea.

“Only me?” The smile that crossed McCoy’s face was lopsided, strangely sincere; again Spock’s reality tilted, dizzying him, as he saw the wrong McCoy in it. 

The doppelganger shushed Spock by covering his lips with one hand before he could demur. 

Spock stared at him, seething, aware that he was more angered by the insight than the slow-fading taste in his mouth. 

“It’ll be a while before I can get it up again to fuck you.” The alternative McCoy got up and went to the wall, where a small minibar waited, fully stocked for the convenience of any resident diplomatic dignitaries. “I think maybe I’ll save that for last.” He brought back a container of water and gave it to Spock, who rose and went to the head to rinse his mouth. 

“Might as well get comfortable while we wait.” McCoy went over to the bed, opening it, and turned up the ambient temperature control. A faint whir announced the atmospheric controls were fully operative. As the temperature slowly began to rise, McCoy stripped himself, letting his uniform trousers fall without apparent self-consciousness. 

He was too thin, Spock noticed at once. His ribs were well-defined and his buttocks sparse. It was not an entirely unpleasant effect. The original doctor was also slight, though perhaps not as undernourished as this one. 

McCoy turned around, raising a brow at Spock. “Like what you see?” He didn’t wait for an answer. “Doesn’t matter, I suppose. Doesn’t to him, anyway. He likes this part best.” He tapped his temple, meaningful. 

Spock made a soft noise of-- he didn’t know what. Approval? Distress? Denial? Fury? The thought of his McCoy subject to mental violation at the hands of an unknown version of himself twisted its way into his consciousness, provoking a truly alarming mixture of feelings. 

“Your McCoy.” The doppelganger smiled. “You keep thinking that.”

Spock felt his jaw tighten. 

“Let’s play a little game,” the false doctor lay down on the bed, arranging himself leisurely on his side. “You’re worried about your doctor. I know what’s probably happening to him. You give me what I want, and I’ll give you what you want. I’ll tell you-- hell, I’ll show you-- what my Spock’ll probably do to him. But if I do, you have to do whatever it is to me.”

Spock considered the proposition, forcing his turbulent emotions brutally into a compartment and shutting it away. 

On one hand, this McCoy would not be likely to show him any real atrocities; he was unlikely to submit himself to anything truly insufferable. On the other hand…. Spock did not relish the idea of being the aggressor in any form, even if he was, in truth, only giving what was commanded by the terms of his bargain. 

He also hated losing, and this was a game he could only lose.

“Whatever is done to him is none of my affair,” Spock rasped. “I am neither responsible nor culpable for it. It will be a private matter between him and any counselor he may choose to consult thereafter.”

“Oh, but it’ll be between the two of you, and you damn well know it.” McCoy lounged at ease, his smile sharp-edged under its disarming twinkle. “He’ll see my Spock every time he looks at you. He’ll remember what was done to him. You know it’s so. After all… _you’ll_ be seeing _me_.”

Spock felt his teeth grit together. Again, just like the real doctor, this man had the knack of getting under his skin. 

“You are determined to destroy my relationship with him.”

“You don’t fucking have one.” McCoy didn’t hesitate, his voice sharp. “Cowards, the both of you.” 

Spock felt the challenge draw him forward, his body propelling itself with a measured heavy tread, rage swelling, seeping out of its carefully constructed compartment, rendering his motions deliberately fluid. 

The McCoy on the bed swallowed thickly, and Spock observed a flush of color entering his cheeks. He shifted, and his hands spread out at his sides, palm up, his vulnerable wrists displayed, ripe to be seized, to be forced over his head. He was naked, ready, vulnerable. He didn’t flinch.

This, Spock’s anger, his aggression: it was wanted.

“I’m seeing some of those chocolate sprinkles I mentioned, Mr. Spock.” McCoy goaded him, his eyes gleaming with desire. “Not so vanilla after all, are you? Still got that cherry to be taken care of, though.” He shifted, his thighs parting. 

Spock stopped perforce, encountering the edge of the bed. His hand rose, almost without his conscious decision to move it. The false doctor watched it approach him, then closed his eyes and turned his face, offering up the psi points. “This is how it will start,” McCoy agreed. “This is how it always starts.”

Spock’s fingertips settled onto flesh slowly, inexorably, ignoring the horrified disgust in his own mind. _I must know._

McCoy drew a deep breath, lips parting, and he opened his thoughts for Spock with fiery anticipation and the ease of long practice.

 _The first time, you-- **he** raped me._ The knowledge arrived calm, matter-of-fact, and there wasn’t any particular resentment attached to the thought; such things were commonplace in his world. Spock recoiled, but the images flowed freely: McCoy stepping into a cabin whose door was decorated with the strange logo of a sword behind a planet Earth. Spock awaiting him, catching his wrist in an iron grip, forcing him back against the wall. This Spock had a beard, well-combed and trimmed; his eyes were aflame with purpose. 

_I require your assistance, doctor._ He laid his fingertips on McCoy’s face, and McCoy was consumed by fire from within.

“It was the pon farr,” McCoy whispered, his lips moving above Spock’s thumb; Spock could still see shadowy images. Spock bearing McCoy down, covering him. Pain. Heat. ….Pleasure, bodies moving together with frantic need. “He took my mind and bound us together. Then I serviced him until the blood fever receded.” 

Unthinkable. “Barbaric,” Spock whispered, eyes closing in grief and shame. 

“Being his has its advantages,” McCoy murmured. He showed a fragmentary stream of images-- men who’d once threatened him now blanched in fear and turned away. A personal guard appeared; a Vulcan, and the threat of assassination attempts stopped. ...Then the images slowed, clarifying. McCoy went to Spock’s cabin again, and this time he went down on his knees at once and served his Spock with gratitude. He lingered in transmitting the details of it, showing how the other Spock had seen him: his cheeks hollowed as he sucked, his half-dazed eyes looking up, the doppelganger Spock’s fists knotted in his hair.

Spock surfaced, hands on the false McCoy’s head, fingers still sunk at the pressure points-- with enough force to bruise. He was hard, painfully so, inside his uniform trousers. McCoy’s eyes blazed at him. “Make me,” he whispered. 

Spock broke. It was, in his defense, a very small break, barely there: the crackle-glaze of lust spreading through the veneer of civilization. He remained absolutely silent.

His hands slid around to cup McCoy’s face; he touched the vulnerable flutter of lids and lashes, the faint stubble on McCoy’s jaw where he hadn’t shaved recently enough, and he trailed past the wet velvet of parted lips. 

His hands tightened. They applied pressure. McCoy surrendered to it at once, moving down. He could feel a smile stretching those mobile human lips, feel McCoy’s shiver of delight. 

McCoy’s mouth flowered open over him, and he hesitated there, hanging fire. Spock exhaled in despair and his hands descended, tightened.

So did McCoy. 

McCoy took him smoothly, without resistance. He sucked, savoring the stretch and burn of his jaw; Spock’s fingers on McCoy’s sweat-damp skin told him everything he did not wish to know. He could not bring himself to remove them. McCoy’s tongue moved like a flame, curling lust around Spock, drawing it from the molten core of his heart. Spock could not look down at him, could not look down at himself. He tipped his head back instead; his throat worked as he gulped for breath. His lips moved. He refused to acknowledge what they might be saying.

McCoy hummed, delighted; he moved slowly. Not enough. He taunted Spock with it-- the sudden lack of suction, the lack of speed and motion, his refusal to do more than tickle and tease.

Spock’s hands came alive like spiders, alien to himself, his fingers splayed. They fastened over McCoy’s skull and under his jaw. They dragged him upward, then thrust him down. 

McCoy gagged, half-choked; lust burst from him in a firecracker pulse that thumped through Spock on shockwaves of mutual desire. Spock gasped and forced himself deeper. His erection moved slickly between McCoy’s lips, constricted in McCoy’s throat as he swallowed.

He broke again, deeper this time, and began to thrust, long battering strokes that made McCoy clutch at his hips, nails digging into his skin in ten little crescents of electric pain. A handful of strokes became a dozen, then twenty. McCoy’s face grew wet, tears sliding out of his eyes and streaming down his cheeks as Spock fucked his mouth, fucked his throat. He never faltered, though, taking it all, those bright, watery blue eyes watching Spock eagerly, predatory, as he shattered.

Spock came in silence, his throat aching with the force of holding back the scream that wanted to well up from his soul and tear its way free. He felt McCoy swallow his semen greedily.

He pulled away, shaking, when he could endure no more of McCoy’s tongue.

McCoy wiped his mouth with the back of his wrist and chuckled-- hoarse and rough around a raw throat. 

“That’s more like it.” McCoy-- the false one, Spock reminded himself with brutality-- slipped upward again, crawling along Spock’s body, and cradled himself against Spock’s side, nestling his head onto Spock’s shoulder, putting his arm over Spock’s belly, his hand on Spock’s ribs. His bare thigh slid over Spock’s thighs, and his warm sigh stirred the fine hairs on Spock’s chest, making him shiver. “We don’t cuddle much back home,” McCoy observed. “But I’ll make an exception for you. Before you ask, no, I don’t know what my Spock will do with your doctor after this. Maybe he’ll put him out in the hall naked with his clothes in his arms.” He sighed and nestled in. Spock could feel that he was tired.

“My doctor will fight,” Spock said, as much to himself as to the other. 

“He’ll lose, Spock.” McCoy told him, drowsily content.

They lay like that for a time, Spock staring at the cabin’s ceiling as his mind whirled in dismay. He could not deny the doppelganger’s words; they filled him with a fear deeper and more terrible than he had ever felt on his own behalf, for he knew without doubt that they were true. 

McCoy began to stir after a time, his thumb stroking back and forth across Spock’s belly at first. Then his hand began to move, a slow, calming caress-- or it might have been, had circumstances been different. 

Spock lay still, allowing it, questioning his motives even as he did so. Why should he keep his word? Curiosity, perhaps. A morbid curiosity, if so.

“That curiosity will be the death of you someday.” McCoy raised himself and began to rummage in the nightstand by the bed. “But we both know it’s not the only reason.” He found a tube of thick salve, testing it between his fingertips. “It’s nice to get what you want without having to take responsibility for your emotions, isn’t it?” Surreal, that pleasant, conversational voice, a velvet sheath over a bitter edge. “Roll over.”

Spock obeyed, sinking his teeth so deeply in his lip he tasted blood. 

“Finish this now,” he said. “Take what you desire, and our bargain is ended.”

McCoy laughed, and his hands fell on Spock, warm and slick. “It’s not that easy, Spock.” He began rubbing the salve into Spock’s taut muscles.

Spock buried his face in the pillow, not much caring whether he could breathe. He did not know if the doppelganger actually enjoyed this, if his gentleness was not wholly a charade, or if he merely attained a perverse pleasure from his attempts to confuse Spock, to delude him, to poison his regard for his own McCoy. 

“I’ll make it good,” McCoy murmured. “You always thought I could, I’ll bet. It’s true. I know exactly what I’m doing. Even better than your doctor. I have the advantage of long experience with turning all that theory into practice.”

Spock declined to respond, trying to relax enough that he would not be injured when the event came to its inevitable conclusion. It was easier than it should have been. The human was truly skilled with his hands, alternate universe or not.

“What reward do you gain from this?” He rasped.

The doctor laughed. “You really _don’t_ understand as much as my own Spock, do you?” His hands never paused, kneading the muscles of Spock’s back. “Don’t you like what I’m doing?”

Spock declined again to provide a response. 

“I know you do. That’s its own reward. I touch you, you touch me. We both win.” Sincerity transmitted itself through those hands as McCoy paused, and again Spock felt himself begin to relax, responding to the brief moment of honesty between them. 

“And then there’s the mindfuck.” McCoy ran his slick fingertips all the way down the length of Spock’s back, circling at the top of his sacrum. 

Spock jerked in spite of himself, startled by the intimacy of those fingers. McCoy smiled. “What’s the matter? Didn’t hurt you, did I?”

Spock re-settled himself, determined not to give him the satisfaction of reacting so strongly again. 

“Tell you what. Since you don’t have the balls to tell him how you feel, I’ll take you just like I think he would,” the alternate McCoy murmured, leaning close. Warm breath tickled his ear. “Then you’ll have something special to remember me by.” His slick fingers slid between the cleft of Spock’s buttocks, gentle and very warm. “Feel free to pretend.”

He lowered himself slowly, and the hot press of his mouth settled at the nape of Spock’s neck. He took his time kissing his way down, lingering at each of Spock’s vertebrae. Lips and tongue lingered, worshipping him. 

Spock shuddered, thinking of his own McCoy-- he was forced to give up thinking of the doctor in any other terms. He couldn’t, not with the tongue teasing at his skin, not with the too-familiar fingers that slowly worked their way down between his buttocks until they began teasing at the pucker hidden there.

“That’s it,” the familiar rough voice purred as the fingers circled. “So perfect.” He lipped tender kisses along one of Spock’s ribs as the finger slowly pressed and withdrew, teasing with the promise of entry. “Waited so long to be here like this. Why didn’t you ever tell me you wanted me this way?”

Spock trembled, half-suffocated by his own stubbornness, his head shoved fiercely into the pillow. His thoughts swam dizzily around inside his mind, deprived of oxygen. The voice that spoke to him was known. Beloved. _Ashayam._

The doctor inhaled sharply as the word echoed silently between them. “Spock…” it came as a whisper: reverent, sweet. The finger pressed in, sinking to the first knuckle. Spock’s eyes stung and he felt dampness soak into the pillow where he attempted to bury his shame. He chose to believe he was merely sweating.

He parted his legs, hoping that somehow he could make this happen faster, so that it would be over, so that he could put it behind him and begin to forget. The doppelganger sank himself deeper, moving with patient care. His teeth grazed lightly at the blade of Spock’s shoulder. He slowly suckled a love bite there.

His finger curved, and Spock grunted, jerking helplessly as pleasure ignited in him, a sudden bright flare like nothing he’d ever felt in his life, his question regarding the rewards of such intimate contact suddenly exposed as foolish indeed. His fingers curved to claws, sinking into the protective shield of the pillow. 

“That’s it.” McCoy delivered the words on a low purr, tender, satisfied. He curled his finger again, and Spock could not entirely stifle his groan; a low sound escaped him. “Let me hear you, Spock.”

He couldn’t help it; the finger felt as though it hooked around his will, sapping it, stealing it away. His erection throbbed painfully, trapped between his belly and the bed. 

McCoy resumed the aborted trail of kisses down Spock’s back; he withdrew the finger and moved his hands to each buttock, pressing to open Spock so that his concealed parts might be seen. Spock could not imagine how this view would yield pleasure, but McCoy’s mind filled with satisfaction, with anticipation. With humor-- both sharp and warm. Malice and tenderness mingled, filling McCoy’s mind with a paradox of intent.

Before Spock could sort one from the other, McCoy leaned in and ran his tongue along the cleft of Spock’s buttocks, and Spock surged forward, startled, driving his erection sharply against the cotton sheet. 

He jerked back from the sensation by instinct, driving himself onto the wicked curl of the doctor’s tongue. McCoy’s hand slid between them, curving around his shaft, and he could not escape; any motion away from one drove him into the other. Spock moaned and felt the pillow rip under the pressure of his fingers, stuffing beginning to spill out. 

“Kneel up.” McCoy kissed the words against him, and he scrambled to his knees, obedient to that familiar voice, acting without thinking. His arms shuddered, so he locked his elbows and raised his head.

“He’d be so hot seeing you like this,” the voice tormented him. “To be the first one inside you, Spock… he’ll never have that now. You’ll never have him as your first.” He stroked his thumb over Spock’s perineum, sending shudders of unwanted pleasure through him, one hand making a slick, wet sound as he lubricated himself. “You’ll have to make do with me.”

Blunt pressure snubbed against Spock, and his final, desperate thought was to fight-- but it was already far too late; the wrong doctor pushed forward and slid inside, and he could think of nothing but his loathing of it, of the terrible error of his choices.

Penetration burned, the doppelganger filling him, stretching him open wide. Spock choked back a despairing cry that had little to do with physical pain. 

He dropped his head, surrendering, punishing himself by abandoning his belated intent to escape. He knelt helpless, shuddering as the doctor’s cock stroked in and out of him, perfect sensation and poison all at once. 

McCoy speeded up, pushing harder, his hips swinging easily. “I own you now, Spock,” he whispered, stroking Spock’s erection with firm, competent pressure. His free hand sought upward, finding a nipple to torment, and Spock choked back a cry as the double’s nails sank deep, sending intense pain zinging straight to his groin. He could not distinguish it from pleasure.

“I win one for once,” McCoy murmured, his aura in Spock’s mind a mixture of perverse tenderness and unholy glee. “Game,” he spoke, thrusting against Spock’s prostate firmly. “Set,” he whispered, sliding his slick hand along Spock’s erection, thumb swiping over the tip. “And match.” He dug his nails into Spock’s nipple, and Spock spent with a gasp, orgasm jerked out of him all at once by those demonically skilled hands.

McCoy kept fucking through the spasms of his climax, holding him upright by the hips while Spock’s muscles sagged, threatening to spill him back onto the mattress. Spock endured, shame burning his cheeks, struggling not to respond, struggling not to react, again too late. 

He was flayed, spent.

McCoy finally climaxed with a low groan, quivering against Spock’s buttocks. When he let go Spock collapsed and McCoy followed him down, snuggling up next to him and gathering Spock against his chest with a sigh of pure contentment. “Sorry ‘bout that.” He chuckled, not sounding remorseful at all. “You’ll just have to forgive me for indulging myself.” He closed his eyes, drowsy.

Spock did not feel particularly forgiving. In fact, quite the opposite. He rolled and caught McCoy by the wrists, forcing him away, over onto his back. McCoy’s eyes sprang open with surprise, then narrowed as a wicked smirk spread across his face. 

“What’s the matter, Spock? Pissed off? Want a little vengeance on the helpless human who just rattled your innate sense of superiority?” His thighs parted, and Spock sank between them easily, his erection wakening again with the unexpected influx of rage and adrenaline, painful but insistent. 

“One of the benefits of lovemaking with a Vulcan,” McCoy whispered. “Little or no refractory period. Did you even know that?”

“Be silent,” Spock grated through clenched teeth. McCoy’s eyes glittered, and he licked his lips. 

“Make me,” he said again, his thighs wrapping behind Spock’s legs, ankles crossing. He bucked up, tipping his head back to offer his vulnerable throat, and Spock took the bait. He bit down, feeling savage pleasure in the way the tender flesh yielded to his teeth.

McCoy writhed, moaning, his own cock soft against Spock’s belly, but he arched upward eagerly in response to the bite. Spock bit again, savage, mindless in his desire for what was offered. He freed one of the doctor’s wrists and seized himself, lining up, ready to plunge, burning with fury--

“Mr. Spock!” Lieutenant Riley’s voice penetrated the wine-dark fog in his brain, and he wondered suddenly how many times Riley had spoken before he was heard. 

“Mr. Spock, we’ve received a communication from Mr. Scott in the other universe. He’s figured out a window for interdimensional phase intersect, sir. If we can bring enough power to bear on their mark, we’ll be able to get the captain back, sir, and the rest of the landing party with him.”

Spock closed his eyes, feeling McCoy tense under him, flesh warm and damp and willing. He let the man’s wrists go and reached to the comm panel.

“When is the window?”

“It’ll open in about an hour, sir, and last for roughly twenty minutes, near as I can tell.”

“Send me your calculations.” Spock gathered his wits sufficiently to scan the screen as they rolled past, aware of McCoy raising his head to look as well. “These seem accurate, lieutenant. I will be with you shortly.”

“Where were we?” McCoy stretched, trying to tempt him, but he could see the man knew he would not succeed again.

Spock ignored him, rising and seeking the binders from before. Finding them at hand, he efficiently clipped the doppelganger to his wrist. 

“If you persist with your advances, doctor, I will incapacitate you forthwith and carry you to the transporter unconscious. Our bargain is ended.” He dragged the false McCoy into the head and they showered, taking awkward turns under the sonics. 

McCoy bathed readily enough, wearing a satisfied half-smirk that did not sit well on his face. Spock refused to respond to his attempts to converse.

“Dress,” he snapped when they were clean, his voice ice-cold, and assisted as required, then re-fastened the binder.

“Well, this has been a pleasant diversion. Better than shore leave,” McCoy preened a little, checking his hair in the mirror. “Sad to see it end, really. But it won’t, not for me. And it doesn’t have to end for you either.” 

He fixed Spock with another charming, jovial smile, but this time Spock could see the devil capering behind those familiar eyes, reveling in its own personal hell, triumphant at having dragged him down to its level. “You can have what you want, you know. I don’t think there’s a universe anywhere that I wouldn’t take whatever I could get from whichever version of you I found there.” He winked. “Keep it in mind.”

He remained mercifully silent as they made their way to the transporter, and stood willingly enough on the platform-- they all did, apparently not wanting to jeopardize their chances at getting home. Spock stared at the chrono, awaiting Mr. Scott’s signal, watching with mounting concern as the seconds ticked away-- and nearly wilted with relief when the panel beeped with the prearranged signal.

He reached for the lever, hearing McCoy chuckle. He raised his hand to send Spock a mocking farewell, and Spock jerked his gaze up with alarm, fearing the man would sabotage the transfer-- but he only waved, a curling motion of all his fingers as the beam engaged.

The transporter panel glimmered, and Spock was keenly conscious of the false McCoy’s eyes fixed on him as he dematerialized. He would be the first thing his own McCoy perceived when he returned.

Their eyes locked as consciousness flowed out, then back in-- Spock would be the last thing each McCoy saw. ….The first thing each McCoy saw. 

McCoy’s wary gaze fell to Spock’s jaw, then rose again as Jim stepped forward, ebullient with relief. 

“Spock!”

“Welcome home, captain.” Spock spoke with quiet courtesy and distinct relief-- but it was McCoy who truly preoccupied him, McCoy who hesitated on the pad, staring at him with an expression reminiscent of a herbivore transfixed by a predator. The hesitation lasted just long enough for him to see McCoy’s adam’s apple bob, just long for him to notice the way McCoy’s shoulders tensed, drawing his spine fully erect. Just long enough for McCoy to deliberately avoid meeting his eyes for a second time.

 _He was right. Something happened between my doctor and the other Spock._ Spock knew it with a certainty that transcended all logic, and his whole being cried out with anguish-- with despair, with regret. With... envy.

McCoy strode off with Jim and the others, and in his voice there was no uncertainty or hesitation. “Straight to sickbay, lady and gentlemen. We all need a full workup, both physical and psychiatric. I’m gonna make sure everything checks out before I let any of us go back on regular duty.”

Spock stood helpless and watched him go, unable to articulate any of his tumult of feelings.

*****

Freed from certain unexpected and distasteful obligations by the departure of the alternative universe landing party, Spock resumed his station on the bridge, waiting to turn the conn over to Captain Kirk. The delay was gratifyingly short; Kirk appeared on the bridge in high spirits. Uhura seemed slightly more subdued, but determined. Of Scott there was no sign.

McCoy trailed in Kirk’s wake, as insolent and abrasive as ever. Spock might have sighed, but he took refuge in iron calm, resolute: he would not reveal his experience with the alternative McCoy.

His report, therefore, remained brief. “We identified the impostors swiftly. Captain Kirk began to behave in an aberrant fashion as soon as he set foot on the bridge. In less than five minutes, Nurse Chapel registered a similar complaint against Doctor McCoy. Lieutenant Uhura objected vociferously, thereby identifying herself as a potential co-conspirator. From there, it was a matter of swift deduction to include Mr. Scott. I applied the Vulcan nerve pinch to the supposed captain, and the group remained sequestered in the brig until such time as this universe’s Mr. Scott contacted the Enterprise, at which time we placed them on the transporter platform to await beam-out and exchange.” 

“What I don’t understand is how you were able to identify our counterparts so quickly.” It had the ring of a backhanded compliment; at least, Spock was willing to take it as such.

“It was far easier for you as civilized men to behave like barbarians than it was for them as barbarians to behave like civilized men. I assume they returned to their Enterprise at the same time you appeared here.” Spock folded his hands behind his back, hoping to hide any trace of nervous tension he might otherwise have betrayed by fidgeting.

“Probably. However, that Jim Kirk will find a few changes, if I read my Spocks correctly.”

Spock used all the willpower he possessed to avoid shooting a glance toward McCoy, but the doctor spoke up immediately anyway, as if he’d sensed the minute avoidance.

“Jim, I think I liked him with a beard better. It gave him character. Of course, almost any change would be a distinct improvement.” McCoy smirked most offensively, and Spock felt his temper kindle. _An improvement? The amoral rapist the other McCoy described was an **improvement?**_

Kirk was speaking, teasing him, trying to take the edge off McCoy’s jibe, but it was too late. Spock did not listen. He leveled a steady gaze on the doctor, exerting every effort to keep his tone mild as he spoke.

“Indeed, gentlemen. May I point out that I had an opportunity to observe your counterparts here quite closely. They were brutal, savage, unprincipled, uncivilized, treacherous. In every way, splendid examples of _homo sapiens_ , the very flower of humanity. I found them quite refreshing.” 

Kirk blinked at him, still feeling humorous, and glanced at McCoy. “I’m not sure, but I think we’ve been insulted.”

McCoy raised a brow, and his dry answer came just a little too fast. “I’m sure.”

Spock’s shift ended soon after that. He departed promptly, intent on returning to his quarters for meditation. He had many emotions to work through and to purge, so many it would keep him busy during his leisure time for numerous weeks, perhaps months. 

He would have been glad to remove the marks the alternative doctor had left upon his body with his hands and teeth. But that would have meant a journey to sickbay, and his own doctor’s inevitable prying questions. Such a thing could not be endured; he would be forced to let them fade naturally. 

Yes. He would require considerable time.


End file.
